This proposal requests funds to assist in the support of the third Gordon Research Conference on the Biology of Mammary Tissue and Milk, scheduled for 9-13 June 1975, at Colby College, New London, New Hampshire. The purpose of this highly successful series is to bring together research biologists from a wide range of subdisciplines for fruitful exchange of ideas and data derived from their diverse approaches to mammary-gland biology. The general theme of the 1975 Conference is control mechanisms in mammary development and function, with approximately a third of the program concerned with failures in these mechanisms that lead to or accompany neoplasia. The funds requested here will be used to support travel and subsistence for invited speakers reporting on aspects of their research on mammary cancer. The discussion topics will include the evolution of prolactin and its action in normal and neoplastic development, the properties and possible origin of preneoplastic lesions in rodent and human mammary glands, biochemical aberrations in preneoplastic and tumor tissues in rodent, dog, and human mammary gland; a session on mammary involution will include a report on subcellular organization in involution and carcinogenesis; a session on metabolic controls will include a talk on the role of cyclic AMP in mammary neoplasia.